Sharepoint 2013 Get Items from a list CSOM :
Soltion :
using (ClientContext ctx = new ClientContext("https://xyz/sites/abc"))
{
    Web web = ctx.Web;
    List list = web.Lists.GetById(new Guid("12345-56655-2sdfgsrg-345235-23ddcs444"));
    var q = new CamlQuery() { ViewXml = "<View><Query><Where><IsNotNull><FieldRef Name='ID' /></IsNotNull></Where></Query></View>"};
    var r = list.GetItems(q);
    ctx.Load(r);
    ctx.ExecuteQuery();                
}

in the above example we are retiving list values where id is not null .


After retriving the list values you can assign this var type result to ineumerable to perform linq or any other data formating,filtering  operations

EX:  IEnumerable<ListItem> lc = r.ToList();